This is a final report for Project 5320-22430-016-07R. The goal of this agreement is to determine an effective radiation dose to control invasive pests in exported commodities, which contributes to objective 1 of the in-house project.

Light brown apple moth, Epiphyas postvittana (LBAM) was first discovered in California in 2007. In New Zealand and Australia, it is an important economic pest of tree fruits such as apples, apricots, citrus, grapes, nectarines, peaches, and pears, and can be found on forestry, vegetable and nursery crops. A major concern with LBAM establishment and spread in California is trade restrictions on fruits and vegetables imposed by importing countries, such as Canada and Mexico. Irradiation is a postharvest quarantine treatment option for exported commodities such as fruits and vegetables to prevent movement of viable LBAM. Eggs, neonates, third instars, and fifth instars were irradiated at target doses of 60, 90, 120, or 150 Gy or left untreated as controls in replicated factorial experiments and survival to the adult stage was recorded. The fifth instar was the most radiotolerant stage commonly found in fruit. Irradiation treatment of approx. 35,000 fifth instars with a radiation dose of 150 Gy resulted in no survival to the adult stage, indicating that this dose can provide quarantine security. In a few crops such as table grapes, pupae may be present in the exported commodity. Large-scale tests are ongoing with late stage pupae to determine a sterilizing dose.